Well packer



Oct. 18, 1966 G. H. TAUSCH ETAL 3,279,544

' WELL PACKER Filed Dec. 19, 1963 6". 1'7. 7271/J c b P. A. fie f/ey INVENTORS ATTO/PA/fy United States Patent 3,279,544 WELL PACKER Gilbert H. Tausch and Phillip R. Hefley, Houston, Tex., V asslgnors to Cameo Incorporated, Houston, Tex., a

corporation of Texas Filed Dec. 19, 1963. Ser. No. 331,748 8 Claims. (Cl. 166216) This invention relates to subsurface well tools and more particularly to an improved tool anchor by which equipment such as a packer assembly is located in casing pipe.

An object of the invention is to provide a simplified casing engageable slip and friction block operative assembly to be slidably sleeved on a tubing string mandrel land releasably secured as a unit therewith for travel within a well casing with the slips and their clutching teeth fully retracted out of wear drag on the casing wall.

Another object of the invention is to provide co-operating friction block and slip members in adjoining end to end relation for independent lateral projectionwithin an outwardly open pocket of a retaining cage and which members are coupled to one another through spring means whose elastic force provides resilient bias outwardly on the block and inwardly on the slip toward bearing abutment with an inner wall portion of a retaining cage and free of wear contact with or resistance to relative movement of the tubing string mandrel.

A further object is to provide a casing engageable cone slip and a drag block separately formed but combined as a working unit with a coil spring held under compression between overlapping end portions of the slip and the block to urge the block outwardly and hold the slip retracted until relative movement of an expander against the cone slip first rocks the slip at its spring engaged end until wickers or teeth at its free end bear on the casing, and thereafter forces the slip into full tooth gripping on the casing.

A preferred embodiment of the invention is illustrated in the accompanying drawing wherein FIG. 1 illustrates the improved packer structure partly in elevation and partly in vertical section; and

FIG. 2 is an exploded perspective view of a pair of easing engageable members comprising a friction block and a co-operating slip.

In FIG. 1 a hook wall packer assembly is illustrated as including a packing collar or packer 1 of resilient rubber or the like in snug embracement on a tubular packer mandrel 2 and in bearing engagement at opposite ends with a pair of relatively axially movable abutment rings 3 and 4 of the fold-back type which control radial distention and outward deformation of the packing collar 1 into and out of sealing relation with the wall of a well bore or tubular casing 5 which lines the well bore wall. The lowermost abutment ring 4 rests on a bearing ring 6 fixed on the upper end of a slip expander tube 7 and is slidable on the lower end portion of the packer mandrel 2 which terminates with a lateral external boss or flange 8 whose upper face provides a pickup shoulder or limit stop engageable with a downwardly facing internal shoulder on the bearing ring 6. The uppermost abutment ring 3 bears upwardly on a seating ring 9 screw threaded or otherwise fixed on the upper end of the packer mandrel 2. At its upper end, the seating ring 9 has a contact surface 10 for reception and transmission of downwardly applied packer setting force when the seat is engaged by an actuating shoulder 11 of an elongated central tube or mandrel 12 constituting a part of the packer assembly.

It is contemplated that opposite ends of the mandrel 12 will be provided with suitable coupling means for connecting it as a part of the tubing string for the production of well fluids and it is further contemplated that the 3,279,544 Patented Oct. 18, 1966 internal diameter of the mandrel 12 will correspond with aligned with one another through the mandrel 2 and the bearing ring 6. This by-pass provided by the annular clearance 14 will be closed upon downward movement of the inner mandrel 12 relative to the packer mandrel 2 which brings the shoulder 11 land to surface 10 into force applying engagement and also locates an annular sealing ring 15 carried by the mandrel 12 below the shoulder 11 into close fitting seating engagement Within the internal surface at the upper end of the mandrel 2 and which surface will preferably be carefully machined for co-operation with the elastic sealing ring or seal 15 in providing a valve closure. Among other things, the bypass provides for equalization of annular pressure on opposite sides of the packer 1, particularly at the time the packer is to be released and the mandrel 12 is raised for lifting the seal 15 outside the packer mandrel 2 and just prior to full contraction of the packing collar 1.

Before downward travel of the tubing mandrel 12 relative to its surrounding packer assembly can occur, the slip expander 7 must be held against movement relative to the casing 5 of the well bore. Initially and during the running in of the well tubing, the components of the packer unit are releasably locked together by a J-slot and pin connection between the tubing mandrel 12 and the lower slip subassembly. As here illustrated, the lower slip subassembly comprises a series of segmental slips 17 having downwardly facing wickers exteriorly thereof as well as retainer lips 21a and a series of co-operating friction blocks 18 arranged in circularly spaced apart pairs of one slip and one friction block, housed within a pocket 40 between radially spaced apart inner and outer tubular cage walls 19 and 20 of a retainer cage 42 and projectable laterally through windows 44 in the outer cage wall 20. Each block or friction shoe 18 is in end to end relation with its co-operating slip 17 and has retainer lips 21 along both side edges, as seen in FIG. 2, for projection behind the cage wall 20 at the vertical margins of its window opening to preclude drop out of the block from the pocket 40. Additionally, each friction block has one or more horizontally extending lips 22 at its side edges, each providing a key for slide reception within a complementary slot or keyway 23 in the outer wall 20. The interconnection 22 and 23 locates the friction block against vertical displacement and precludes contact of its upper edge with the bottom of the slip in order that the slip will be free for independent lateral movement without frictional braking resistance thereon.

The underside of the cage pocket 40 between the walls 19 and 20 is closed by an annular exterior boss 24 on the inner wall and which receives one or more fastening screws 25 extending inwardly through the outer wall 20. This boss 24 also has a pair of diametrically opposite counterbored openings to house and retain headed pins 26 overlaid by the outer wall 20 and projected inwardly into I-slots 27 in the outer surface of the tubing mandrel 12. Conveniently, the J-slots 27 are cut into a tubular sleeve 28 fitted and welded on the lower portion of the Each of the several slips 17 is a tapered segmental wedge and its back face is axially inclined in mating relation with a frusto-conical surface 30 externally of the terminal portion of the slip expander 7 and which is telescoped within the cage outer wall 20. An external upwardly facing shoulder 31 on the expander is for safety pickup abutment with a limit stop ring or spacer 32 fitted inside the upper portion of the retainer cage wall 20.

At their adjacent ends, the companion complementary slip and friction block of each set have axially overlapping portions between'which is located a coil spring 33 under compression for elastically biasing the friction block outwardly and the slip inwardly. The outermost coils of the spring 33 fit with slight clearance within a depression or socket 46 on the! back of the friction block 18 and the innermost spring coils surround a raised pilot or boss 34 on an inwardly disposed and axial extension or dependent car on the slip 17. In this fashion the slip and block are interlocked with the spring and with one another. In slip contracted relationship, the slip extension 35 bears inwardly on the inner cage wall 19 and is held out of contact with the tubing string mandrel 12. The fit of the cage wall 19 and the mandrel 12 provides sufficient clearance as not to interfere with relative rotation and axial movements. Also, in slip contracted relationship the width dimensions are such that the outer sharp pointed tooth formations are held back protectively out of wear contact with the well bore wall. Preferably, the slip dependent extension 35 is relatively short and underlies only the immediately adjacent end portion of the axially longer friction block 18 and one or more additional springs 36 are interposed between the friction block and the inner cage wall 19 to maintain adequate outward pressure and straight-line projection of the friction block in the radial direction.

With the lock pins 26 and their J-slots 27 locking the external and contracted packer component to the tubing mandrel 12, as seen in FIG. 1, the assembly can be coupled in a tubing string and lowered through the well bore with only the friction blocks 18 in drag contact with the well casing. On reaching the selected depth at which the packer is to be set, the tubing string is manipulated to release the pin 26 from the short portion of the J- slot connection. Such manipulation of the structure illustrated will involve a slight elevation of the tubing string relative to the slip cage subassembly whose friction block 18 action resists its displacement relative to the casing wall 5. Thereafter, a partial rotation of the tubing string brings its long run of the J-slot into alignment with the pin 26 whereupon the tubing string and the mandrel 12 will be lowered relative to the pin 26 and the cage and slip subassembly. With such tubing down travel, the surface 30 slides downwardly behind and pushes the slips 17 outwardly against the inward bias of the coil springs 33 on the dependent extension 35 of the slips. Initially, the dependent extensions 35 will tend to fulcrum on the inner cage wall 19 as the upper portion of the slipis swung outwardly into contact. or near .contact with the casing wall. With continued outer wedging action and descent of the expander 7, the springs 33 will yield for a firm seating of the slips 17 throughout their longitudinal extent on the casing wall for a positive hold and resistance of the packer subassembly against downward displacement. With the lower slip securely anchored, further down travel of the expander 7 and the packer collar abutment ring 4 is stopped and endwise pressure on the packer collar 1 results in an increase in packer width and its distention radially into tight sealing contact with the casing wall 5. At this time the upper end of the clearance 14 is closed by the sealing ring 15 and the weight of the tubing string maintains the packer 1 in set condition. 7

Subsequently, retrieval will merely require tubing string elevation. As soon as the sealing ring 15 is shifted above the upper ring 9 of the packer subassembly, annulus pressures on opposite sides of the packer will become 4 equalized and allow elastic recovery of the packer collar 1. Engagement of the abutment ring 29 with the bottom flange 8 of the packer mandrel 2 raises the mandrel and the upper abutment 3 and thereafter the flange .8 picks up the ring 6 for raising the slip expander 7 to permit contraction of the holding slips 17. Further upward movement brings the latch pins 26 into the bottoms of their respective J-slots and either or both the contactjwith the pins 26 or the contact of the shoulder 31 with thering 32 will carry the cage subassembly upwardly with the tubing string. v

The combination of the friction blocks and slips as here disclosed permits a short unitized assembly with the advantages of compactness and easy passage and insures initial gripping engagement by the slips without large downward pressure on the packing collar untilthe slips are securely set. In addition, the arrangement enables free rotation of the tubing mandrel relative to the external packer component and without frictional resistance to mandrel contact with either the slips or the friction blocks.

Although this disclosure has been limited to a single preferred embodiment, the invention is capable of such modification and variation as come within the scope of the appended claims.

What is claimed is:

1. In a subsurface well tool, a unitary'assembly of slips and friction blocks comprising a tubular cage having a side wall window and an internal retainer element projecting across a portion of the window and radially spaced inwardly from the window containing wall, a segmental slip and friction block mounted in end to end succession within and for lateral projection through said window and provided with'overlapping portions at their adjacent ends, such portion of the slip being interposed between the block portion and said internal retainer element for inward retracted stop abutment with the latter and spring means yieldably biasing the slip portion inwardly and said block portion outwardly in relation to the cage..

2. In a subsurface well tool, a casing engageable friction block, a slip having an expander engageable back surface and. an. extension underlying the friction block, spring means active on said extension to resiliently contract the slip and active on said friction block to project the same laterally of the tool and a locating cage having laterally spaced apart intermost and outermost wall portions of which the outermost portion contains a window which guidably receives said friction block and the slip and accommodates their outward projection, the innermost wall portion extending behind said extension and providing a limit stop to slip retraction.

3. In a subsurface well tool,'a mandrel, a cage having an inner wall slidably fitted on the mandrel and an outer wall radially spaced from the inner wall to provide a pocket therebetween, said outer wall having anaopening therein providing a window for said pocket, a slip and a friction block retained in the pocket and independently laterally shiftable through the window, an inwardly disposed extension on the slip in underlying relation to the friction block and engageable for inward stop abutment with the cage-inner wall, a compression coil spring interposed between said extension and said friction block and seating formations on the friction block and the extension having internested fitment with the opposite ends of said coil spring.

4. In a subsurface well tool, a friction slide block and a slip in juxtaposed relation with one another, an extension on said slip projecting behind vthe'friction block, spring means interposed between the extensionand the friction block, a retainer cagefenclosing a locating pocket in which the slip and block are housed and having an inwardly disposed bearing abutment engageable with the slip, extension, said cage including an outer wall having a window opening at the pocket for projection therethrough of the friction'blockand the slip, retainer lips on the friction block extending laterally thereof for out- Ward, limit stop abutment with the cage wall inner face bordering said opening and interlocking key and groove formations on the cage wall and friction block extending in the direction of block projection and slidably keying the block in the cage.

5. In a subsurface well tool as in claim 4, said spring means including a coil spring under compression having interlocking nested bearing fitment at opposite ends with the friction block and said slip.

6. In a subsurface well tool as in claim 5, wherein said interlocking nested fitment at one spring end includes a socket on the back of the friction block in nested fitment with the adjoining spring coils and at the opposite spring end includes a forward projection of the slip extension in nested fitment with the adjoining spring coils.

7. In a subsurface well tool, a mandrel having a peripheral J-slot, a cage assembly slidably sleeved on the mandrel and provided with an inwardly projected pin fitted to said J-slot for releasably locating the cage on the mandrel, said cage assembly including an inner wall having slide bearing on the mandrel and an outer wall radially spaced from the inner wall to provide a pocket therebetween having one end open and a window opening through the outer wall, a slip expander axially movable through said open end into and out of slip expansion engagement, a friction block and an expander engageable slip fitting said pocket for independent lateral projection through the window, means accommodating lateral movement of the friction block but precluding its separation from the cage and comprising block carried retainer lips engageable with the cage outer wall at a given limit of block projection and interfitting key and groove formations on the cage outer wall and the block extending in the direction of block projection and means joining the slip and block against displacement axially of the mandrel and comprising an extension on the slip positioned between the inner wall and the friction block, spring means interposed between the slip extension and said friction block to bias the slip and the friction block inwardly and outwardly respectively and locating interconnections between the spring means and the slip and between the spring means and the friction block.

8. In a subsurface well tool as in claim 7, wherein said spring means is a coil spring in compression and the locating interconnections comprise a 'boss on the slip extension which projects into one end of the coil spring and a socket onthe friction block within which the other end of the coil spring is nested.

References Cited by the Examiner CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner. 

1. IN A SUBSURFACE WELL TOOL, A UNITARY ASSEMBLY OF SLIPS AND FRICTION BLOCKS COMPRISING A TUBULAR CAGE HAVING A SIDE WALL WINDOW AND AN INTERNAL RETAINER ELEMENT PROJECTING ACROSS A PORTION OF THE WINDOW AND RADIALLY SPACED INWARDLY FROM THE WINDOW CONTAINING WALL, A SEGMENTAL SLIP AND FRICTION BLOCK MOUNTED IN END TO END SUCCESSION WITHIN AND FOR LATERAL PROJECTION THROUGH SAID WINDOW AND PROVIDED WITH OVERLAPPING PORTIONS AT THEIR ADJACENT ENDS, SUCH PORTION OF THE SLIP BEING INTERPOSED BETWEEN THE BLOCK PORTION AND SAID INTERNAL RETAINER ELEMENT FOR INWARD RETRACTED STOP ABUTMENT WITH THE LATTER AND SPRING MEANS YIELDABLY BIASING THE SLIP PORTION INWARDLY AND SAID BLOCK PORTION OUTWARDLY IN RELATION TO THE CAGE. 